<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script type="text/javascript">
			var a = 0 ;
			var b = 1000;
			while(b<=5000){
				a++;
				b = b * ( 1+0.05 );
			}
			alert(a);
		</script>
	</head>
	<body>
	</body>
</html>
